Radioactive wastes are generated by a number of industrial, medical and electric power generating activities. Periodically, these wastes are processed and prepared for shipment to a disposal site. Because of their radioactive nature, it is important to limit the exposure of employees who process and handle them. It is also important to process the wastes so that they remain stable during shipping and disposal until the radionuclides present decay to nominal levels. Therefore, techniques have been developed to process wastes quickly and efficiently.
There exists a variety of plastic and metal containers used to ship and store radioactive wastes. In particular, certain sludge and ion exchange media slurry wastes are dewatered in shipping containers that are provided with one or more sets of dewatering filters. For a slurry application, an empty container that is already fitted on the inside cavity with dewatering filters and headers is connected to a filling device. The dewatering headers inside the container are manually connected to the corresponding dewatering connections on the filling device, commonly called a fillport. The fillport dewatering connections are connected to a pump or vacuum source.
To fill the container, the waste slurry is pumped through the fillport into the container. As the water-slurry level increases inside the container, the dewatering filters are gradually covered. A float type level transmitter or switch is provided to prevent overfilling the container. A pump or vacuum source is energized to draw excess water from inside the container through the dewatering filters, internal headers, and fillport connections. The slurry is thus dewatered to the extent necessary for shipment and disposal. Once the excess or "free" water is removed from the container, the container contains only dewatered, solid materials. The fillport is then lifted and the dewatering lines that are connected to the dewatering headers inside the container and the fillport are manually disconnected.
The filled container is then closed by putting a lid over the opening. The lids for plastic containers have external threads. The lid is then screwed in the opening on top of the container that has a mating internal threads. Lids of metal containers are typically snapped or bolted on
Fillports typically are held to the container simply by their weight or perhaps by two or more hold-down bolts or toggles. The bolted fillport is secured by manually threading bolts into mating threaded holes on the container. The toggle type fillport is secured by means of two or more toggles or cam arms provided with manual or air-cylinder-operated lever arms.
Dewatering connections typically comprise mating cam and groove type fittings, such as CAM-LOK fittings by Dixon. Occasionally other "quick-disconnect" type fittings are used, such as hydraulic fittings by Parker. These type fittings still all require manual (and literally, handson) make-up and disassembly.
Dewatering filters typically comprise disposable plastic depth-type filters Following each dewatering application the filters that become plugged are removed from the container and discarded. New filters are then installed in the containers that are to be reused.
A variety of such containers, fillports and lids are available from several manufacturers including Chem-Niuclear, Nukem, and Studsvik.